“Even if there is only one possible unified theory, it is just a set of rules and equations. What is it that breathes fire into the equations and makes a universe for them to describe?” -Stephen Hawking

One of the greatest discoveries of the 20th centuries was not only that there were just four fundamental forces describing all of nature, but that two of them — the electromagnetic and the weak force — unify into a single “electroweak” force at high energies. Given the equivalences between electric charges in the strong nuclear force sector and the electroweak sector, could there be a grand unification between those as well?

The pattern of weak isospins, weak hypercharges, and strong charges for particles in the SU(5) model, also known as the Georgi-Glashow charges. Image credit: Wikimedia Commons user Cjean42 under a c.c.a.-s.a. 3.0 license, created from Garret Lisi’s Elementary Particle Explorer.

The pattern of weak isospins, weak hypercharges, and strong charges for particles in the SU(5) model, also known as the Georgi-Glashow charges. Image credit: Wikimedia Commons user Cjean42 under a c.c.a.-s.a. 3.0 license, created from Garret Lisi’s Elementary Particle Explorer.

In a great theoretical development, Grand Unification Theories (GUTs) became all the rage, making bold predictions like additional bosons, flavor-changing neutral currents, and proton decay. But in the more than 30 years since their inception, the ideas of GUTs have all fallen flat, implying the question of whether the entire concept of unifying forces and interactions into larger groups and structures is completely wrongheaded.

The four fundamental forces. Image credit: Wikimedia Commons user Kvr.lohith, under a c.c.a.-s.a. 4.0 international license.

The four fundamental forces. Image credit: Wikimedia Commons user Kvr.lohith, under a c.c.a.-s.a. 4.0 international license.

Experiments and measurements don’t lie, but it’s up to the scientists who work on it to choose to go in a different direction. Perhaps it’s truly time.

Comments

  1. #1 MP
    July 7, 2016

    Steven Hawking is adding a philosophical bent towards physics? 🙂

  2. #2 MP
    July 7, 2016

    Pardon me. Stephen.

  3. #3 Denier
    United States
    July 7, 2016

    Trying to find the nexus between the electromagnetic force and the strong force seems to get most of the attention, but it is the relationship between the strong force and gravity that I find intriguing.

    The color force binding quarks together inside particles does not diminish with distance and is ridiculously strong. The nuclear force is not as strong as the color force and does diminish with distance. Yet both are just different manifestations of the strong force mediated through gluons either directly or bound up in pi and rho mesons.

    Now here is where gravity comes in. Gravity is MUCH weaker than even the nuclear force, which in turn is weaker than the color force. The QM mediator of gravity is the graviton, which just happens to look like a double copy of a gluon.

    I don’t find fault with the thinking of theorists who believe the universe is like Taco Bell. There is a whole menu of different looking things but when you break it down it is just the same seven ingredients in different presentations.

  4. #4 See Noevo
    July 7, 2016

    “It might not be comforting, especially initially, but … there’s no compelling reason to think _____ _______ is anything other than *a theoretical curiosity* and a physical dead-end.”

    This is a test. Fill in the blank!
    ……………………………………………

    The answer in this particular blog is “grand unification”!
    …………………………………………….
    However, the same wording, but with different blank filling, could probably be used as the final flourish to many of Ethan’s blog posts.

  5. #5 Michael Kelsey
    SLAC National Accelerator Laboratory
    July 7, 2016

    @Deceiver #4: “Christain fundamentalism”. Am I right?

  6. #6 dean
    July 7, 2016

    Michael, christian fundamentalism is a physical dead-end, and a dead end for intellectual development, but it’s a curiosity only as far as it makes thinking people wonder “how can those fundamentalists be so ignorant?”

  7. #7 See Noevo
    July 7, 2016

    Off topic, a little help needed…

    I’d post this question myself but I’m not allowed to comment within Greg Laden’s blogs.

    Greg had a great preoccupation with and focus on the presidential race recently. In fact, he may have gone a week or three without a single climate change post!!!
    Just posts about the primaries and the presidential race.

    The question for Greg is:
    Do you agree that Hillary Clinton should NOT have been indicted by James Comey?

  8. #8 Narad
    July 7, 2016

    This is a test. Fill in the blank!

    “catechism worship”

  9. #9 Narad
    July 7, 2016

    ^ Hmph; <u> tags don’t work. I wonder if <und> does.

  10. #10 Narad
    July 7, 2016

    The question for Greg is:

    The answer for S.N. is: Fυck off, nobody’s posting your comments for you someplace where you’re not welcome.

  11. #11 See Noevo
    July 7, 2016

    Re #4:

    “… no compelling reason to think _____ _______ is anything other than *a theoretical curiosity* and a physical dead-end.”

    Some recent candidates for blank filling:

    “Venus, not Earth, may have been our Solar System’s best chance at life”

    “Ceres’ bright spots are salts; likely due to subsurface water”

    “Can Gravitational Waves Let Us Peek Inside A Black Hole?”

    “Does Earth really have a second Moon?”

    “Origin Of LIGO’s Merging Black Holes Finally Discovered! …
    So how did these black holes come to be? After much numerical study, it APPEARS THAT young, metal-poor stars about 40-100 solar masses… Finally, in the final fractions of a second, those ripples in spacetime were enough to vibrate our detectors here on Earth BY LESS THAN A THOUSANDTH THE WIDTH OF A PROTON.”
    …………..
    Priceless.

  12. #12 Dean
    July 8, 2016

    Yes sn, all the things you list are amazing. It is astounding what can be done by people with an education, and the correct tools, can do.

    It is also amazing what ignorant people can dismiss without any serious argument or data, simply because they won’t take the time to study (as you demonstrate with each of your posts).

  13. #13 eric
    July 8, 2016

    This is a test. Fill in the blank!

    Answering SN?

  14. #14 Narad
    July 8, 2016

    I’m sort of following the humor in the Shaw illustration, but does anyone get the “sinh” → “sihn” change?

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